The present invention relates generally to microelectromechanical systems having at least one flexure element and more particularly to a method of making a microelectromechanical system using a flexure protection layer.
During the formation of microelectromechanical system (MEMS) devices, flexure thicknesses should be carefully controlled to maintain a consistent spring constant. Various etching processes may be used in formation of MEMS devices. The various etching processes may decrease the thickness of the flexure. This may cause the spring constant to vary. Even small deviations of the spring constant are crucial because the spring constant has an inverse cubic dependence on the thickness of the flexure. Additional layers on the flexure may be beneficial, however, they may contribute to the flexure thickness and thus deviations in flexure spring constant. Further, subsequent etching processes may attack the additional layers; therefore the problem of spring constant variation may not be adequately solved.